macOS / Restore SSH compatibility after upgrading to macOS 13 (Ventura)

Objective

• To provide instruction on resolving the error: Unable to negotiate with <server IP address> port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss

User

• Miami University Community

Scope

• macOS Ventura introduces a new version of the OpenSSH client that blocks ssh-rsa connections by default

Environment

• macOS computers running macOS Ventura

Instructions 

1. Edit your ~/.ssh/config file using the text editor of your choice
   • If you do not have a config file in your ~/.ssh directory, you can create one
2. Add the following lines under the Host * entry:

   • Host *
     HostKeyAlgorithms +ssh-rsa
     PubkeyAcceptedKeyTypes +ssh-rsa